Virtual machine live migration is an important feature that it allows a network administrator to move virtual machines to another physical host without interrupting operation during the live migration. However, if there is a security device, such as gateway or firewall, protecting the virtual machine in front of the original physical host, once the virtual machine is moved to another physical host, the data connections to the virtual machine would be disconnected. This would interrupt data traffic and stop current operation of the virtual machine.
Traditionally, virtual machine live migration is detected by querying a virtual machine management system and retrieving the operation information. This is done by using the API (Application Programming Interface) being provided by the virtual machine management system. However, each virtual machine management system provides a different access method and the API may change overtime. This method also requires network security devices constantly connect to the virtual machine management system, which is not efficient and sometime it is not practical.